Breeding biology of the Helmeted Manakin Antilophia galeata in an ecotone between the Atlantic Forest and the Cerrado

Abstract

Manakins (Pipridae) are well-known by their promiscuous mating system. Nonetheless, scarce evidence suggests that the Helmeted Manakin Antilophia galeata, the only dichromatic manakin widely distributed in the South American Cerrado, is monogamic. We studied the breeding biology of the Helmeted Manakin in the state of Minas Gerais, southeastern Brazil. We found 17 nests, which are built in the forest undergrowth (usually below 3 m height). Nests are a cup attached by its top lip usually in the angle of a forked branch. The nest attachment zone is made mostly of spider silk. The structural zone is constructed with dry broad leaves, leaf petioles and horsehair fungus, which were bind together by a considerable amount of spider silk. The outer (decorative) zone is made with some hanging dry broad leaves, frequently forming a tail. Clutch size is always two (n = 12), and eggs are long oval, with a ground color in different shades of beige, marked with irregular spot, blotches and, sometimes, streaks ranging from light to dark brown. Mean eggs measurements were 23.9 x 16.3 mm (n = 14), weighting 3.3 g (n = 10). Eggs are laid once each day and hatching is synchronous. Females are the sole responsible for nest building (which usually took 10 days), incubation (18.5 days), and nestling care (18.3 days). The simple percentage of successful nests (n = 11) was 27% and predation was the main cause of nest failure. The breeding season extends from the second half of August to the first half of January. Renesting after loss of a first clutch is a common strategy and we recorded up to three nesting attempts for a single female. We present evidence that the Helmeted Manakin is promiscuous, as usual for a dichromatic manakin.